The results of several necropsy studies of the accuracy of coronary angiography are summarized. Although there is variation in the degree to which coronary angiography has been found to be inaccurate by necropsy examination, all necropsy studies have demonstrated at least some degree of inaccuracy of this diagnostic modality. More recent studies have demonstrated that such inaccuracies may occur in as many as 39% of examined segments of coronary artery. While all segments of the coronary arterial tree have been noted to be sites of inaccurate angiographic evaluation, the left main coronary artery appears to be particularly treacherous as a site for angiographic evaluation of narrowing. Reasons for the discrepancies between angiography and necropsy include the diffuse nature of the atherosclerotic process, the eccentric and often slit-like shape of the residual non-occluded coronary lumen, and, in the case of the left main coronary artery in particular, the short length and varying courses of this vessel. The routine use of multiple obliquities and nonconventional views has been proposed as the most successful way to improve the accuracy of coronary angiography.